Ag/ZrO2/MWCNT Nanocomposite as Non‐Platinum Electrocatalysts for Enhanced Oxygen Reduction Reaction

Abstract Although the development of non‐platinum electrocatalysts for oxygen reduction reaction (ORR) has made some satisfactory progress, it is still a challenge to get a non‐platinum catalyst with higher activity and better stability. In this study, a novel non‐platinum catalyst composed of silver (Ag) nanoparticles and zirconia (ZrO 2 ) coated on the multi‐walled carbon nanotubes (MWCNTs) catalyst (denoted as Ag/ZrO 2 /MWCNTs) is obtained by simple hydrothermal and photochemical methods. This catalyst shows more positive onset potential of 0.97 V (vs RHE), higher limiting current density of 6.4 mA cm −2 and lower H 2 O 2 yield of 3.9 % than that of commercial platinum‐carbon (Pt/C) catalyst (0.93 V, 6.0 mA cm −2 and 4.8 % obtained from our test results). Electrochemical tests also show that ORR follows a four‐electron pathway. Moreover, the long‐term stability and methanol tolerance are also better compared with Pt/C. The results of theoretical calculations and the characterizations reveal that the enhanced ORR performance is attributed to the robust skeleton of MWCNTs benefitting for the uniform growth of ZrO 2 and the improved conductivity of the catalyst, and the enhanced ability of Ag for O 2 adsorption and OH desorption by the introduction of ZrO 2 . This work may serve as a reference to design and prepare the composite electrocatalysts with the high ORR performance.